Six of the seven studies showed positive but modest effects on quality of care for some primary outcome measures, but not all. One study found no effect on quality of care. Poor study design led to substantial risk of bias in most studies. In particular, none of the studies addressed issues of selection bias as a result of the ability of primary care physicians to select into or out of the incentive scheme or health plan.
At best, then, these results are “modest” and mixed. When looked at alongside significant design flaws, particularly the failure to take into account selection bias, there is no convincing evidence, conclude the review authors, that P4P consistently improves quality of care.
The studies cited in the review looked mainly at performance. What's missing from the discussion in the review is any attempt to distinguish between performance and real quality. If we have learned anything at all from our experience with core measures and public report cards it's that performance does not equal quality. If the evidence that P4P improves performance is scant it's somewhere between slim and none for quality.
More from Medscape and DB's Med Rants.